Direct Mailing

[Jonatas Silva]

I was driving for dollar around my neighborhood and found 6 houses , i sent a letter for each property. 

one of the letter returned as NOT DELIVERABLE AS ADDRESSED UNABLE TO FORWARD.

i double checked the address, look it up on google. not sure why came back.

What would you do next? drive to the address and knock on the door? or drop off the letter in the mailbox?

any guide? thank you in advance. 

[Michael Herr]

You should try sending the letter to the owner of the house,  which could be something other than the subject address. 
Go on the county tax assesors website, figure out the owner's address and mail there. 
For such a targeted 6 houses, figure out the owner's name and figure out thier phone number and give them a call.